Blasting cartridge



Septu l2, 1933-` A. w. HELMHoL-rz ET AL 1,926,282

-BIQASTING CARTRIDGE I l F11-ed July 1e, 1951 v g Z@ l5 AWA AW 9% \\v/// mw wwwwv^w Patented Sept. 12 33 WuHeolta di Dent Ferrell,

Harrisburg, duplication .italy ,16, 1193i. Serial' No. 55149854 This invention relates to an improved form of cartridge for blasting purposes adaptable to the mechanical pressure system oi blasting and covers improvements over our former Patent No.

1,569,226, issued January l2, 192e, relating to a mechanical pressure blasting method and a device foi-carrying out the method. The present improvements include more particularly a new and novel design of blasting container which has several important advantages over former `constructions.

It is one object to obtain a blasting container which is cheaply and easily made.

A It is another object to provide a blasting container which is automatically held inthe drill or bore hole in the material t'o oe blasted and thus eliminates the objections encountered heretoiore oi containers or shells being thrown from the bore holes by too shallow a hole or insumcient tamping. The flying of the shell or cartridge oi. the bore hole fromk any cause whatsoever is instrumental in damaging' the container or shell itself or other machinery in its path and is also dangerous in causing injury to workmen. It is another object of the improved form of construction to eliminate damage and destruction to the'pipe lines connecting this shell to the source Aoi? pressure, thus providing for al cheaper cost of operation and maintenance cost.

Other objects and advantages of the present improvements 'will be more readily understood from the following description taken'in connection with the attached drawing, in which Figure 1 is an elevation illustrating the blasting container in place in a drill hole;

Figure 2 is a longitudinal section of the blasting container;

Figure 3 is a transverse section taken on the plane indicated 3-3 in Figure 2, and

Figure d is e transverse section taken on the saine plane looking in the opposite direction, as indicated by the arrows d-.

In general, blasting shells used in our method are arranged so that the venting of the shell is at the inner end of the bore hole and as a result, when the rupture oi the venting diei: in the shell occurs, a reaction takes place which tends to force the shell out oi the hole and il the hole is too short or the tamping too light, the shell wl bev readily iorced out by the blasting pressure produced. This reaction is also asststed by the expanding gases between the inner end of the shell and the inner end oi? ,the drill hole., in such case the shell is very liable (ci. is)

to be blown out with suflicient force to injure the shell itself or machinery or workers in its path. l

In the present application the shell or container is a rigid metallic barrel having one end @o completely closed and the opposite end adapted to holda removable and renewable venting disk. The shell is of strong material, greater than the venting disk, so that it is substantially indestructible and may be used an indenite number ci' times. According to the present improvements the inlet connection from the source of pressure to the shell is at the e end of the shell as the venting disk. i

Referring to Figure 1', l0 is the roof of the coal m breast, 1 2 is the oor or bottom and 14 is the coal face; The coal face is undercut as at 16. The drill hole i8 is placed in accordance with the judgment oi the workman and is generally directed into the coal face at the top portion and slightly in a diagonally upwarddirection. An imaginary vertical plane, indicated by a dotted line 20, extends from the inner end of the undercut 16 towards the roof 10 and deiines a so-called solid portion of the coal i'ace or breast. The drill hole. @o

18 extends somewhat beyond the plane 20 to accommodate a part of the blasting shell 22 so that the venting end 24 is near the plane 20, just how near will depend somewhat upon the particular nature of coal or material to be blasted. The 35 pipe line 26 extends from the source of pressure to a connection of the shell at the venting end thereof. lThe remainder 'of the drill hole 18 is lled with tamping 28. In the present case the tamping is only necessary to prevent loss of gas gg after venting oi the shell and is not required to hold the shell in place. Pipe line 26 communicates with the pressure source and conducts the blasting medium under high pressure, such as 5000 pounds per square inch, to the blasting shell g5 22 until the rise in pressure in the shell is sucient to rupture the 4venting disk and release the gas, whereupon that portion o? the coal from the plane 2o` to the face ld is forced outwardly and downwardly and thrown away from the main ion hind and no noxious gases are created. Y The oper- N5 ation is similar to hydraulic blasting except that it has the additional advantage of using an eirpansible medi instead of a non-expansible fluid, such as water.

The container is shown in detail in Figure 2 and im includes a rigid container-barrel 22 having an interior cavity on the longitudinal axisof the barrel. The cavity may be oiset with respect to the outside diameter of the barrel at its open end, leaving a thinner wall on one side than on the other, as is shown in Figure 2. The open end is provided with an internally-threaded portion 32. The thicker side of the wall is provided with a passage 3e communicating with the cavity 30 and a pipe line 26 having a threaded connection at 36 with the shell 22. An exteriorly threaded shoulder member or throat piece 38 is inserted in the barrel and is preferably cemented in position to insure a tight connection. The inner end of theopening through the shoulder is rounded and tapered, as at il), to diminish the resistance to flow of the blasting medium from the shell. The blasting medium passes through the circular orifice d2 of the shoulder which is of suicient area to permit escape of the blasting medium. The outer end of the shoulder 38 has a circular knife edge il which is concentric with respect to the axis of the shoulder but is eccentric with respect to the axis oi the barrel 22. The

' knife edge is a ridge'of hard metal and makes for a gas-tight joint with the venting dish d5, which is of softer metal. It is necessary, in obtaining a tight metal-to-metal joint between knife edge of shoulder 38 and the dish e6, to avoid relative rotation between the parts, while the dist; is being pressed into sealing engagement therewith,

and in the present case relative rotation is prevented by means of a hardened pin 48 inserted in the shoulder and extending partly beyond the knife edge se so that as the disk 46 is pressed ber is a hollow plug, either forged or machined o! suitable material, having an external thread for engaging the threaded portion of the barrel.

The inner end 56 of the cap member, which prees against the disk 46, is a hardened portion forming an annular edge against which' the disk 46 will shear when the desired pressure for rupture is reached. ,The cap member has a'straight circular passage 58 permitting the ruptured portion of the disk 46 to be blown wholly out of the cap member and additional lateral openings 60 are provided to permit the escape of the blasting medium from the cap member.

It will be apparent that we have described a l. Blasting apparatus comprising a closed container adapted to ht in the drill hole, said container having rigid walls integrally closing the inner end of said container adjacent the inner end of said drill hole and a rupturable wall at the outer end of said container, a pipe line connected to the outer end of said container adapted lo deliver gas under pressure into said container whereby the release of said gas from said container through rupture of said rupturable wall tends to hold said container in said drill hole and prevent buckling oi said pipe.

2. The process oi shooting coal or like material which comprises, providing a drill hole in the material to he shot, providing a shell in said drill hole containing a .conned non-explosive Viluid medium under relatively high pressure, causing the release of said medium only at a point adje.n cent the outer end of said shell whereby to exert in addition to a shooting force, a force acting to hold said shell in said drill hole.

3. The process of shooting coal or like material which comprises, providing a drill hole in the material to be shot, providing a shell in said drill hole containing a non-explosive uid medium under pressure conned by a rupturahle wall facing outwardly ci said drill hole, thereafter providing a predetermined vhigh :duid pressure within said ,shell and causing the rupture oi' said wall and the release of said duid only in the outward direction oi said drill hole whereby to exert in addition to a shooting force, a force acting to hold said shell in said drill hole.

d. The process oi shooting coal or like material which comprises, providing a drill hole in the material to he shot, providing s shell in said drill hole containing a vnon-explosive uld inedium under pressure conned by a rupturable wall facing outwardly of said drill hole, forcing uid under pressure into said shell until a predetermined high pressure is reached therein and then causing said wall to rupture and to release said duid only in the outward direction of said drill hole whereby to exert in addition to a shooting force, a force acting to hold wid shell in said drill hole., 

